Robots are currently used in manufacturing facilities for many varied tasks. To those not directly involved in the acquisition, set up, programming, and operation it would seem that robots could be trained to do almost anything. However, those skilled in the art of robotics know of many hurdles to very large-scale implementation of robotics, particularly in low volume applications. Current robotics are not reasonably affordable until the task desired to be automated needs to be done approximately 2.5 million times per year.
A robot with a sufficiently robust design to cycle every four seconds can accomplish approximately 13,000 tasks per day on two eight hour shifts, or three million tasks in one year. A robot of this description typically costs about $150,000. Over a typical two-year amortization, this robot costs about 2.5 cents per insertion for amortization costs. The robotic technician's training costs, his maintenance time, power costs, and others probably cost about the same or another $150,000 over two years.
In almost all cases, the task performed by a robot can be done at half the speed with a human. That is, from the example above, the same three million pieces over one year can be done by two people per shift on two shifts, for four man-years. To do this task for two years, six million pieces will be made using eight person-years. In today's world economy, it is very easy to find labor for $3,000 per year or $24,000 for eight-person years. Therefore, in this example, it costs $300,000 ($150,000 robot+$150,000 technician costs) minus $24,000 (or $276,000) more to use robotics.
Although it can be argued the robot has twice that useful life, the next application typically involves a new feeder ($15,000), a new program (one man-week of an engineer whose cost is at least $1,000 per week), a new set of grippers (typically $1,000 minimum), and miscellaneous locators and fixtures. Add to this the ongoing support and maintenance and it is easy to see that the ongoing tasks can cost 2.5 to 3 cents per task.
Other hidden costs include machine malfunction. If a crash occurs due to a broken wire or human error the machine can cause one of the mechanical components to move or be bent by only a few thousandths of an inch. This causes significant cost for parts, re-teaching, and downtime. Some breakdowns are as simple as a bug landing on a sensor, and although it subsequently flies away, a day or more of production may be lost due to the damage caused by the sensor misreading and the lost time troubleshooting this type intermittent problem.
These problems are compounded when lower volume production runs are required, when running only 100,000 tasks whether in one month or one year, it is virtually impossible to justify setting up a robot when a human can do the task. With most simple tasks, a human can be trained in 30 minutes and produce 3,000 tasks per shift easily, and nearly 100,000 tasks can be accomplished in about 30 days. To robotically automate this task, it would typically take the same amount of time to design and build a simple feeder and jaw set and to program the new application. And the people that do these tasks typically are paid much more than the human that would normally perform the task. If you only spend $20,000 for hardware and human time, the 100,000 tasks cost 20 cents each.